Phytostabilization
Phytostabilization is mostly used for the remeditation of soil, sediment and water. It depends on the roots ability to limit contaminted mobility in the soil. It can occur through sorption, precipitation, complexaction, or metal valence reduction (Berti and Cunningham, 2000).The plants purpose in phytostabilization is to decrease the amount of water percolation through the soil matrix, which may result in the formation of hazardous leachate and prevent soil erosion and spread pf toxic metal to other areas. Phytostabilization is not the removal of metal contaminates of the site, but more the stabilization and reduction of the contamination. Also the plant needs a dense root system to stabilize the soil and prevent erosion (Cunningham et al., 1996).

This figure below shows the process of which the plant stabilizes the contaminants.
http://www.biology-online.org/js/tiny_mce/plugins/imagemanager/files/boa001/phytoremediationf07.JPG
external image phytoremediationf07.JPG


Advantages
- It may combine treatment with ecosystem restoration . The technology usually enhances the soil fertility.
- Stabilization reduces mobility. This may be a risk, of organic contaminants without removing the from their location.
- Material handling is limited compared to other remedial technologies, such as excavation. Therefore costs will be typically lower.

Disadvantages
- If soil additives are used, they may need to be peri-odically reapplied. This is to mantain the effectiveness of the immobilization.
- The site must be monitored perpetually o make sure the stabilization conditions continue because the contaminants are left in place.
- Toxic effects may prevent plants from growing until extensive amendment application reduce their bioavailability to plants. This will occur if the contamination concentration elevate.

Rebecca D'Arcy